(a) Field
Exemplary embodiments of the invention relate to an electrochemical cell, a battery module including the electrochemical cell, and a battery pack including the battery module.
(b) Description of the Related Art
Unlike a primary battery that cannot be recharged, a rechargeable battery may be repeatedly charged and discharged. A small-capacity rechargeable battery is widely used for small portable electronic devices such as mobile phones, notebook computers, camcorders, and the like, and a large-capacity rechargeable battery is typically used as a motor-driving power source for hybrid vehicles and electric vehicles.
Recently, among such rechargeable batteries, a metal-air battery using oxygen in air as a positive active material has been actively researched. The metal-air battery is a battery including a negative electrode capable of absorbing/releasing ions and a positive electrode using the oxygen in the air as an active material.
In such a metal-air battery, a reduction/oxidation reaction of the oxygen inflowing from the outside is generated in the positive electrode, the oxidation/reduction reaction of the metal is generated in the negative electrode, and chemical energy generated by such reactions is extracted as electrical energy. The metal-air battery may absorb the oxygen during the discharging and emit the oxygen during the charging. As described above, since the metal-air battery uses the oxygen in the air, the energy density of the battery may be dramatically improved. For example, the metal-air battery may have high energy density of more than that of a conventional lithium ion battery by several times.
Also, because the metal-air battery has a low possibility of ignition due to a high temperature, the metal-air battery has high stability, and is operated by only the absorption/releasing of the oxygen without the use of a medium metal, a possibility of environmental pollution is low. According to these various merits, many studies of the metal-air battery are being currently undertaken.